Two proteins, dysferlin and synaptotagmin VII, are implicated in vesicle-mediated membrane healing and contain C2 domains, which are known to be calcium binding domains. Study of the muscular dystrophy protein, dysferlin, in conjunction with synaptotagmins, will allow me to probe the mechanisms of calcium dependent vesicular fusion in membrane repair. I will first characterize the Drosophila dysferlin homolog. By means of an in vitro membrane-healing assay, I will also probe the role of C2 domains in membrane repair through RNA interference in Schneider 2 cells. This in vitro assay will enable me to determine whether or not C2 domain proteins are functionally distinct, functionally interchangeable, or functionally redundant in the cell. In addition to the study of membrane repair, these studies may be helpful in understanding mechanisms that cause some forms of muscular dystrophy. Recently identified mutations in dysferlin suggest a novel mechanism for the pathogenesis of Limb-Girdle Muscular Dystrophy type 2B.